CNET published a review of the new Aliph Jawbone 2 Bluetooth headset.

Quote from the review: "We should note that there's no real volume rocker since the Jawbone 2 is configured to adjust the volume automatically according to the environment, thanks to its Noise Assassin technology. If you wish to turn the Noise Assassin off, you can do so by hitting the Noise Assassin button.
And then if you wish to adjust the volume manually, the Noise Assassin button also acts as a singular volume control, meaning you have to cycle through different volume levels to get to the right volume. All that said, we would've preferred a volume rocker anyway, for ease of use. "
Read the full review on CNET.